It is generally known to provide multiple optical elements on or in one or more surfaces of optical substrates including films, components or wave guides for directing light passing through the optical substrates. At least some of the optical elements may have at least two surfaces that come together to form a ridge and are quite small relative to the length and width of the optical substrates.
It is generally known to cut or form a predetermined pattern of cavities of such optical element shapes in a flat sheet or plate using a milling or laser cutter and using the cut optical element shapes in the sheet or plate to form a corresponding pattern of optical elements on or in optical substrates. A drawback to this method is the difficulty and expense of cutting or forming cavities of certain types of optical element shapes including particularly those having at least two surfaces that come together to form a ridge and are quite small relative to the length and width of the optical substrates. Also the spinning tools needed to make these geometric shapes are quite expensive and difficult to make, and have a relatively short useful life because of breakage or the like, which further adds to the cost of making cavities having these geometric shapes.